CN202759386U

Movatterモバイル変換

Info

Publication number: CN202759386U
Application number: CN201220393557.2U
Authority: CN
Inventors: 左德祥; 刘洋; 杨勇
Original assignee: Shenzhen TCL New Technology Co Ltd
Current assignee: Shenzhen TCL New Technology Co Ltd
Priority date: 2012-08-09
Filing date: 2012-08-09
Publication date: 2013-02-27
Anticipated expiration: 2022-08-09

Abstract

Translated fromChinese

本实用新型公开一种反激式开关电源电路及反激式开关电源，反激式开关电源电路包括供电端、反激式变压器、主电压输出电路、主控制电路和变压器初级控制电路，反激式变压器包括初级绕组和第一次级绕组；主电压输出电路包括第一整流二极管、第一滤波电容及一电子开关，第一滤波电容为极性电容；第一整流二极管的阳极与第一次级绕组的同名端连接，第一次级绕组的异名端接地，第一整流二极管的阴极与电子开关的一端连接，电子开关的另一端与第一滤波电容的正极连接，第一滤波电容的负极接地，电子开关的控制端与主控制电路连接。本实用新型在保证电路可靠性的同时，降低了电路的成本。

The utility model discloses a flyback switching power supply circuit and a flyback switching power supply. The flyback switching power supply circuit includes a power supply terminal, a flyback transformer, a main voltage output circuit, a main control circuit and a transformer primary control circuit. The type transformer includes a primary winding and a first secondary winding; the main voltage output circuit includes a first rectifier diode, a first filter capacitor and an electronic switch, and the first filter capacitor is a polar capacitor; the anode of the first rectifier diode is connected to the first The same-name end of the primary winding is connected, the opposite-name end of the first secondary winding is grounded, the cathode of the first rectifier diode is connected to one end of the electronic switch, the other end of the electronic switch is connected to the positive pole of the first filter capacitor, and the first filter capacitor The negative electrode is grounded, and the control terminal of the electronic switch is connected with the main control circuit. The utility model reduces the cost of the circuit while ensuring the reliability of the circuit.

Description

Translated fromChinese

反激式开关电源电路及反激式开关电源Flyback switching power supply circuit and flyback switching power supply

技术领域technical field

本实用新型涉及电源技术领域，尤其涉及一种反激式开关电源电路及反激式开关电源。The utility model relates to the technical field of power supplies, in particular to a flyback switching power supply circuit and a flyback switching power supply.

背景技术Background technique

反激式开关电源是指当其反激式变压器的初级绕组（原边）导通时，其次级绕组（副边）截止，此时该反激式变压器处于储能状态，而当反激式变压器的初级绕组（原边）截止时，其次级绕组（副边）导通，此时该反激式变压器将之前所储存的能量释放给负载，使负载工作。The flyback switching power supply means that when the primary winding (primary side) of the flyback transformer is turned on, its secondary winding (secondary side) is cut off. At this time, the flyback transformer is in the state of energy storage, and when the flyback transformer When the primary winding (primary side) of the transformer is cut off, its secondary winding (secondary side) is turned on. At this time, the flyback transformer releases the previously stored energy to the load to make the load work.

如图1所示，图1是现有技术中一种反激式开关电源电路的电路结构示意图，该电路包括供电端101、反激式变压器102、主控制电路103、主电压输出电路104、待机电压输出电路105、主电压输出端106、待机电压输出端107及变压器初级控制电路108。As shown in Figure 1, Figure 1 is a schematic diagram of the circuit structure of a flyback switching power supply circuit in the prior art, the circuit includes apower supply terminal 101, aflyback transformer 102, amain control circuit 103, a mainvoltage output circuit 104, A standbyvoltage output circuit 105 , a mainvoltage output terminal 106 , a standbyvoltage output terminal 107 and a transformerprimary control circuit 108 .

具体地，反激式变压器102包括初级绕组S1'、第一次级绕组S21'及第二次级绕组S22'，主电压输出电路104包括第一整流二极管D1'、第一滤波电容C1'及一电子开关K1'，第一滤波电容C1'为极性电容，第一整流二极管D1'的阳极与反激式变压器102的第一次级绕组S21'的同名端连接，第一次级绕组S21'的异名端接地，第一整流二极管D1'的阴极与电子开关K1'的一端连接，电子开关K1'的另一端与主电压输出端106连接，电子开关K1'的控制端与主控制电路103连接；第一滤波电容C1'的正极与第一整流二极管D1'的阴极连接，第一滤波电容C1'的负极接地，待机电压输出电路105包括第二整流二极管D2'及第二滤波电容C2'，第二滤波电容C2'为极性电容，第二整流二极管D2'的阳极与反激式变压器102的第二次级绕组S22'的同名端连接，第二次级绕组S22'的异名端接地，第二整流二极管D2'的阴极与第二滤波电容C2'的正极连接，且与待机电压输出端107连接，第二滤波电容C2'的负极接地；变压器初级控制电路108包括第一MOS管Q1'和采样电阻RS'，第一MOS管Q1'为PMOS管，第一MOS管Q1'的漏极与反激式变压器102的初级绕组S1'的同名端连接，初级绕组S1'的异名端与供电端101连接，第一MOS管Q1'的栅极与主控制电路103连接，其源极与采样电阻RS'的一端连接，且与主控制电路103连接，采样电阻RS'的另一端接地。图1所示电路还包括输出容性负载C3'，输出容性负载C3'的一端连接于电子开关K1'和主电压输出端106之间，输出容性负载C3'的另一端接地。Specifically, theflyback transformer 102 includes a primary winding S1', a first secondary winding S21' and a second secondary winding S22', and the mainvoltage output circuit 104 includes a first rectifier diode D1', a first filter capacitor C1' and An electronic switch K1', the first filter capacitor C1' is a polar capacitor, the anode of the first rectifier diode D1' is connected to the end of the same name of the first secondary winding S21' of theflyback transformer 102, the first secondary winding S21 The opposite end of 'is grounded, the cathode of the first rectifier diode D1' is connected to one end of the electronic switch K1', the other end of the electronic switch K1' is connected to the mainvoltage output terminal 106, and the control end of the electronic switch K1' is connected to themain control circuit 103 connection; the anode of the first filter capacitor C1' is connected to the cathode of the first rectifier diode D1', the cathode of the first filter capacitor C1' is grounded, and the standbyvoltage output circuit 105 includes a second rectifier diode D2' and a second filter capacitor C2 ', the second filter capacitor C2' is a polar capacitor, the anode of the second rectifier diode D2' is connected to the same-named end of the second secondary winding S22' of theflyback transformer 102, and the second secondary winding S22' has a different name The terminal is grounded, the cathode of the second rectifier diode D2' is connected to the positive pole of the second filter capacitor C2', and is connected to the standbyvoltage output terminal 107, and the negative pole of the second filter capacitor C2' is grounded; the transformerprimary control circuit 108 includes a first MOS Tube Q1' and sampling resistor RS', the first MOS tube Q1' is a PMOS tube, the drain of the first MOS tube Q1' is connected to the same-named end of the primary winding S1' of theflyback transformer 102, and the different end of the primary winding S1' The terminal is connected to thepower supply terminal 101, the gate of the first MOS transistor Q1' is connected to themain control circuit 103, its source is connected to one end of the sampling resistor RS', and is connected to themain control circuit 103, and the other end of the sampling resistor RS' One end is grounded. The circuit shown in FIG. 1 also includes an output capacitive load C3', one end of the output capacitive load C3' is connected between the electronic switch K1' and the mainvoltage output terminal 106, and the other end of the output capacitive load C3' is grounded.

其中，上述电子开关K1'为MOS开关管，当电子开关K1'为MOS开关管时，MOS开关管的源极与第一整流二极管D1'的阴极连接，MOS开关管的漏极与主电压输出端106连接，MOS开关管的栅极与主控制电路103连接。Wherein, the electronic switch K1' is a MOS switch tube. When the electronic switch K1' is a MOS switch tube, the source of the MOS switch tube is connected to the cathode of the first rectifier diode D1', and the drain of the MOS switch tube is connected to the main voltage output Theterminal 106 is connected, and the gate of the MOS switch is connected to themain control circuit 103 .

图1所示电路中的第一滤波电容C1'代表该反激式开关电源的电源板上的电容，电子开关K1'控制主电压输出端106的电压输出，由于该电子开关K1'设于第一滤波电容C1'和输出容性负载C3'之间，使得第一滤波电容C1'在电子开关K1'的导通瞬间将存在很大的电流，使得电子开关K1'在其导通瞬间将受到大电流的冲击，从而降低了电子开关K1'的可靠性。现有技术中，为了提高电子开关K1'的可靠性，通常是采用大功率的MOS开关管来实现，然而，大功率的MOS开关管的价格昂贵，从而导致电路成本的增加。The first filter capacitor C1' in the circuit shown in Figure 1 represents the capacitance on the power supply board of the flyback switching power supply, and the electronic switch K1' controls the voltage output of the mainvoltage output terminal 106, because the electronic switch K1' is located at the first Between a filter capacitor C1' and the output capacitive load C3', there will be a large current in the first filter capacitor C1' when the electronic switch K1' is turned on, so that the electronic switch K1' will be subjected to The impact of a large current reduces the reliability of the electronic switch K1'. In the prior art, in order to improve the reliability of the electronic switch K1 ′, a high-power MOS switch tube is usually used for implementation. However, the high-power MOS switch tube is expensive, which leads to an increase in circuit cost.

实用新型内容Utility model content

本实用新型的主要目的是提供一种反激式开关电源电路，旨在保证反激式开关电源电路可靠性的同时，降低反激式开关电源电路的成本。The main purpose of the utility model is to provide a flyback switching power supply circuit, aiming at reducing the cost of the flyback switching power supply circuit while ensuring the reliability of the flyback switching power supply circuit.

为了达到上述目的，本实用新型提出一种反激式开关电源电路，包括用于提供供电电压的供电端、用于对所述供电电压进行反激式变压的反激式变压器、用于输出主电压的一主电压输出电路、以及一主控制电路和一变压器初级控制电路，所述反激式变压器包括初级绕组和第一次级绕组，所述主控制电路控制所述主电压输出电路输出所述主电压，以及根据所述反激式变压器的初级绕组的反馈电流，经所述变压器初级控制电路控制所述初级绕组的导通时间；In order to achieve the above purpose, the utility model proposes a flyback switching power supply circuit, including a power supply terminal for supplying a power supply voltage, a flyback transformer for performing a flyback transformation on the power supply voltage, and a power supply terminal for outputting A main voltage output circuit of the main voltage, and a main control circuit and a transformer primary control circuit, the flyback transformer includes a primary winding and a first secondary winding, the main control circuit controls the output of the main voltage output circuit The main voltage, and according to the feedback current of the primary winding of the flyback transformer, control the conduction time of the primary winding through the primary control circuit of the transformer;

所述主电压输出电路包括第一整流二极管、第一滤波电容及一电子开关；所述第一整流二极管的阳极与所述反激式变压器的第一次级绕组的同名端连接，所述第一次级绕组的异名端接地，所述第一整流二极管的阴极与所述电子开关的一端连接，所述电子开关的另一端与所述第一滤波电容的一端连接，所述第一滤波电容的该端为所述主电压输出电路的电压输出端，所述第一滤波电容的另一端接地，所述电子开关的控制端与所述主控制电路连接。The main voltage output circuit includes a first rectifier diode, a first filter capacitor and an electronic switch; the anode of the first rectifier diode is connected to the same-named terminal of the first secondary winding of the flyback transformer, and the first The opposite end of the primary winding is grounded, the cathode of the first rectifier diode is connected to one end of the electronic switch, the other end of the electronic switch is connected to one end of the first filter capacitor, and the first filter This end of the capacitor is the voltage output end of the main voltage output circuit, the other end of the first filter capacitor is grounded, and the control end of the electronic switch is connected to the main control circuit.

优选地，所述第一滤波电容为极性电容，所述第一滤波电容的正极经所述电子开关与所述第一整流二极管的阴极连接，所述第一滤波电容的负极接地。Preferably, the first filter capacitor is a polar capacitor, the anode of the first filter capacitor is connected to the cathode of the first rectifier diode through the electronic switch, and the cathode of the first filter capacitor is grounded.

优选地，所述反激式开关电源电路还包括用于输出待机电压的待机电压输出电路，所述反激式变压器还包括第二次级绕组；所述第二次级绕组的同名端与所述待机电压输出电路连接，所述第二次级绕组的异名端接地。Preferably, the flyback switching power supply circuit also includes a standby voltage output circuit for outputting a standby voltage, and the flyback transformer also includes a second secondary winding; the end of the second secondary winding with the same name as the The standby voltage output circuit is connected, and the opposite terminal of the second secondary winding is grounded.

优选地，所述反激式开关电源电路还包括一输出容性负载，所述输出容性负载的一端与所述第一滤波电容的正极连接，所述输出容性负载的另一端接地。Preferably, the flyback switching power supply circuit further includes an output capacitive load, one end of the output capacitive load is connected to the positive pole of the first filter capacitor, and the other end of the output capacitive load is grounded.

优选地，所述供电端与所述反激式变压器的初级绕组的异名端连接，所述初级绕组的同名端经所述变压器初级控制电路与所述主控制电路连接。Preferably, the power supply end is connected to the opposite end of the primary winding of the flyback transformer, and the same end of the primary winding is connected to the main control circuit via the primary control circuit of the transformer.

优选地，所述待机电压输出电路包括第二整流二极管及第二滤波电容，所述第二滤波电容为极性电容；所述第二整流二极管的阳极与所述反激式变压器的第二次级绕组的同名端连接，所述第二整流二极管的阴极与所述第二滤波电容的正极连接，所述第二滤波电容的正极为所述待机电压输出电路的电压输出端，所述第二滤波电容的负极接地。Preferably, the standby voltage output circuit includes a second rectifier diode and a second filter capacitor, the second filter capacitor is a polar capacitor; the anode of the second rectifier diode and the second secondary of the flyback transformer The terminal of the same name of the primary winding is connected, the cathode of the second rectifier diode is connected to the anode of the second filter capacitor, the anode of the second filter capacitor is the voltage output terminal of the standby voltage output circuit, and the second The negative pole of the filter capacitor is grounded.

优选地，所述变压器初级控制电路包括第一MOS管和采样电阻；所述第一MOS管为PMOS管；所述第一MOS管的漏极与所述反激式变压器的初级绕组的同名端连接，其栅极与所述主控制电路连接，其源极与所述采样电阻的一端连接，且与所述主控制电路连接，所述采样电阻的另一端接地。Preferably, the primary control circuit of the transformer includes a first MOS tube and a sampling resistor; the first MOS tube is a PMOS tube; the drain of the first MOS tube is connected to the same-named terminal of the primary winding of the flyback transformer Its gate is connected to the main control circuit, its source is connected to one end of the sampling resistor and connected to the main control circuit, and the other end of the sampling resistor is grounded.

优选地，所述主电压输出电路中的所述电子开关为MOS开关管，所述MOS开关管的源极与所述第一整流二极管的阴极连接，其漏极与所述第一滤波电容的正极连接，其栅极与所述主控制电路连接。Preferably, the electronic switch in the main voltage output circuit is a MOS switch, the source of the MOS switch is connected to the cathode of the first rectifier diode, and the drain of the MOS switch is connected to the first filter capacitor The anode is connected, and its gate is connected with the main control circuit.

本实用新型还提出一种反激式开关电源，所述反激式开关电源包括反激式开关电源电路，所述反激式开关电源电路包括用于提供供电电压的供电端、用于对所述供电电压进行反激式变压的反激式变压器、用于输出主电压的一主电压输出电路、以及一主控制电路和一变压器初级控制电路，所述反激式变压器包括初级绕组和第一次级绕组，所述主控制电路控制所述主电压输出电路输出所述主电压，以及根据所述反激式变压器的初级绕组的反馈电流，经所述变压器初级控制电路控制所述初级绕组的导通时间；The utility model also proposes a flyback switching power supply, the flyback switching power supply includes a flyback switching power supply circuit, and the flyback switching power supply circuit includes a power supply terminal for providing a power supply voltage, for A flyback transformer for performing flyback transformation on the supply voltage, a main voltage output circuit for outputting main voltage, a main control circuit and a transformer primary control circuit, the flyback transformer includes a primary winding and a first a secondary winding, the main control circuit controls the main voltage output circuit to output the main voltage, and controls the primary winding through the primary control circuit of the transformer according to the feedback current of the primary winding of the flyback transformer the turn-on time;

本实用新型提出的反激式开关电源电路，由于将主电压输出电路中的电子开关设于主电压输出电路的第一滤波电容和输出容性负载的前面，从而使得本实用新型避免了该电子开关在其导通瞬间而受到大电流的冲击，从而增加了该电子开关的可靠性，即本实用新型可以选用功率较小的MOS开关管作为主电压输出电路中的电子开关，从而使得本实用新型在提高电路可靠性的同时，降低了电路的成本。The flyback switching power supply circuit proposed by the utility model avoids the electronic The switch is impacted by a large current at the moment of its conduction, thereby increasing the reliability of the electronic switch, that is, the utility model can select a MOS switch tube with a small power as the electronic switch in the main voltage output circuit, so that the utility model can The new type reduces the cost of the circuit while improving the reliability of the circuit.

附图说明Description of drawings

图1是现有技术中一种反激式开关电源电路的电路结构示意图；Fig. 1 is a schematic diagram of the circuit structure of a flyback switching power supply circuit in the prior art;

图2是本实用新型反激式开关电源电路较佳实施例的电路结构示意图；Fig. 2 is the schematic diagram of the circuit structure of the preferred embodiment of the utility model flyback switching power supply circuit;

图3是本实用新型反激式开关电源电路较佳实施例工作于连续电流模式时的相应电流波形图；Fig. 3 is the corresponding current waveform diagram when the preferred embodiment of the flyback switching power supply circuit of the present invention works in the continuous current mode;

图4是本实用新型反激式开关电源电路较佳实施例工作于断续电流模式时的相应电流波形图；Fig. 4 is the corresponding current waveform diagram when the preferred embodiment of the flyback switching power supply circuit of the present invention works in the discontinuous current mode;

图5是本实用新型反激式开关电源电路较佳实施例工作于临界连续模式时的相应电流波形图。Fig. 5 is a corresponding current waveform diagram when a preferred embodiment of the flyback switching power supply circuit of the present invention works in the critical continuous mode.

本实用新型目的的实现、功能特点及优点将结合实施例，参照附图做进一步说明。The realization of the purpose of the utility model, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

具体实施方式Detailed ways

以下结合说明书附图及具体实施例进一步说明本实用新型的技术方案。应当理解，此处所描述的具体实施例仅仅用以解释本实用新型，并不用于限定本实用新型。The technical solution of the utility model is further described below in conjunction with the accompanying drawings and specific embodiments of the description. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

图2是本实用新型反激式开关电源电路较佳实施例的电路结构示意图。FIG. 2 is a schematic diagram of the circuit structure of a preferred embodiment of the flyback switching power supply circuit of the present invention.

参照图2，本实用新型反激式开关电源电路包括供电端201、反激式变压器202、主控制电路203、主电压输出电路204、待机电压输出电路205、主电压输出端206、待机电压输出端207及变压器初级控制电路208。其中，反激式变压器202包括初级绕组S1、第一次级绕组S21及第二次级绕组S22。Referring to Fig. 2, the flyback switching power supply circuit of the present utility model includes apower supply terminal 201, aflyback transformer 202, amain control circuit 203, a mainvoltage output circuit 204, a standbyvoltage output circuit 205, a mainvoltage output terminal 206, a standbyvoltage output Terminal 207 and transformerprimary control circuit 208. Wherein, theflyback transformer 202 includes a primary winding S1 , a first secondary winding S21 and a second secondary winding S22 .

其中，供电端201用于提供供电电压，反激式变压器202用于对供电端201的供电电压进行反激式变压，主电压输出电路204用于输出主电压，待机电压输出电路205用于输出待机电压，主控制电路203用于控制主电压输出电路204输出所述主电压，主控制电路203还用于根据反激式变压器202的初级绕组S1的反馈电流，经变压器初级控制电路208控制反激式变压器202的初级绕组S1的导通时间。Wherein, thepower supply terminal 201 is used to provide the power supply voltage, theflyback transformer 202 is used to perform flyback transformation on the power supply voltage of thepower supply terminal 201, the mainvoltage output circuit 204 is used to output the main voltage, and the standbyvoltage output circuit 205 is used for To output the standby voltage, themain control circuit 203 is used to control the mainvoltage output circuit 204 to output the main voltage, and themain control circuit 203 is also used to control the primary voltage through the transformerprimary control circuit 208 according to the feedback current of the primary winding S1 of theflyback transformer 202 The conduction time of the primary winding S1 of theflyback transformer 202 .

具体地，供电端201与反激式变压器202的初级绕组S1的异名端连接，初级绕组S1的同名端经变压器初级控制电路208与主控制电路203连接；反激式变压器202的第一次级绕组S21的同名端经主电压输出电路204与主电压输出端206连接，第一次级绕组S21的异名端接地；反激式变压器202的第二次级绕组S22的同名端经待机电压输出电路205与待机电压输出端207连接，第二次级绕组S22的异名端接地。Specifically, thepower supply terminal 201 is connected to the opposite-named end of the primary winding S1 of theflyback transformer 202, and the same-named end of the primary winding S1 is connected to themain control circuit 203 through theprimary control circuit 208 of the transformer; the first time of theflyback transformer 202 The terminal with the same name of the primary winding S21 is connected to the mainvoltage output terminal 206 through the mainvoltage output circuit 204, and the terminal with the same name of the first secondary winding S21 is grounded; the terminal with the same name of the second secondary winding S22 of theflyback transformer 202 is connected with the standby voltage Theoutput circuit 205 is connected to the standbyvoltage output terminal 207, and the opposite terminal of the second secondary winding S22 is grounded.

本实用新型反激式开关电源电路还包括一输出容性负载C3，输出容性负载C3的一端与第一滤波电容C1的正极连接，输出容性负载C3的另一端接地。The flyback switching power supply circuit of the utility model also includes an output capacitive load C3, one end of the output capacitive load C3 is connected to the positive pole of the first filter capacitor C1, and the other end of the output capacitive load C3 is grounded.

其中，上述主电压输出电路204包括第一整流二极管D1、第一滤波电容C1及电子开关K1，第一滤波电容C1为极性电容。具体地，第一整流二极管D1的阳极与反激式变压器202的第一次级绕组S21的同名端连接，第一次级绕组S21的异名端接地，第一整流二极管D1的阴极与电子开关K1的一端连接，电子开关K1的另一端与第一滤波电容C1的正极连接，且与主电压输出端206连接及经输出容性负载C3接地，第一滤波电容C1的负极接地，电子开关K1的控制端与主控制电路连接。本实施例中的电子开关K1为MOS开关管，该MOS开关管的源极与第一整流二极管D1的阴极连接，其漏极与第一滤波电容C1的正极连接，且与主电压输出端206连接，其栅极与主控制电路203连接。Wherein, the mainvoltage output circuit 204 includes a first rectifier diode D1, a first filter capacitor C1 and an electronic switch K1, and the first filter capacitor C1 is a polar capacitor. Specifically, the anode of the first rectifier diode D1 is connected to the same-name end of the first secondary winding S21 of theflyback transformer 202, the opposite-name end of the first secondary winding S21 is grounded, and the cathode of the first rectifier diode D1 is connected to the electronic switch One end of K1 is connected, the other end of the electronic switch K1 is connected to the positive pole of the first filter capacitor C1, and is connected to the mainvoltage output terminal 206 and grounded through the output capacitive load C3, the negative pole of the first filter capacitor C1 is grounded, and the electronic switch K1 The control terminal is connected with the main control circuit. The electronic switch K1 in this embodiment is a MOS switch tube, the source of the MOS switch tube is connected to the cathode of the first rectifier diode D1, the drain is connected to the anode of the first filter capacitor C1, and is connected to the mainvoltage output terminal 206 connected, and its gate is connected to themain control circuit 203.

上述待机电压输出电路205包括第二整流二极管D2及第二滤波电容C2，第二滤波电容C2为极性电容。具体地，第二整流二极管D2的阳极与反激式变压器202的第二次级绕组S22的同名端连接，第二整流二极管D2的阴极与第二滤波电容C2的正极连接，且与待机电压输出端207连接，第二滤波电容C2的负极接地。The standbyvoltage output circuit 205 includes a second rectifier diode D2 and a second filter capacitor C2, and the second filter capacitor C2 is a polar capacitor. Specifically, the anode of the second rectifier diode D2 is connected to the terminal with the same name of the second secondary winding S22 of theflyback transformer 202, the cathode of the second rectifier diode D2 is connected to the positive pole of the second filter capacitor C2, and is connected to the standby voltage output Theterminal 207 is connected, and the negative pole of the second filter capacitor C2 is grounded.

上述变压器初级控制电路208包括第一MOS管Q1和采样电阻RS。本实施例中，第一MOS管为PMOS管。具体地，第一MOS管Q1的漏极与反激式变压器202的初级绕组S1的同名端连接，第一MOS管Q1的栅极与主控制电路203连接，第一MOS管Q1的源极与采样电阻RS的一端连接，且与主控制电路203连接，采样电阻RS的另一端接地。The transformerprimary control circuit 208 includes a first MOS transistor Q1 and a sampling resistor RS. In this embodiment, the first MOS transistor is a PMOS transistor. Specifically, the drain of the first MOS transistor Q1 is connected to the terminal of the same name of the primary winding S1 of theflyback transformer 202, the gate of the first MOS transistor Q1 is connected to themain control circuit 203, and the source of the first MOS transistor Q1 is connected to One end of the sampling resistor RS is connected to themain control circuit 203 , and the other end of the sampling resistor RS is grounded.

本实用新型反激式开关电源电路有三种工作模式，分别为连续电流模式、断续电流模式和临界连续模式。The flyback switching power supply circuit of the utility model has three working modes, namely continuous current mode, discontinuous current mode and critical continuous mode.

其中，连续电流模式为：本实用新型反激式开关电源电路处于满载或者重载状态时，变压器初级控制电路208中的第一MOS管Q1的开关占空比较大，从而使得当主电压输出电路204中的第一整流二极管D1未关断时，变压器初级控制电路208中的第一MOS管Q1已经导通。因此，当本实用新型反激式开关电源电路工作于连续电流模式时，其反激式变压器202的初级绕组S1和第一次级绕组S21的电流没有同时为0的情况。当本实用新型工作于连续电流模式时，其反激式变压器202的初级绕组S1和第一次级绕组S21的电流波形如图3所示，图3中的Ip为反激式变压器202的初级绕组S1的电流波形，Is为反激式变压器202的第一次级绕组S21的电流波形，Ton为第一MOS管Q1的导通时间，Toff为第一MOS管Q1的截止时间，Ts为第一MOS管Q1开关周期。Wherein, the continuous current mode is: when the flyback switching power supply circuit of the present invention is in a full-load or heavy-load state, the switch duty ratio of the first MOS transistor Q1 in the transformerprimary control circuit 208 is relatively large, so that when the mainvoltage output circuit 204 When the first rectifier diode D1 in the transformer is not turned off, the first MOS transistor Q1 in the transformerprimary control circuit 208 is turned on. Therefore, when the flyback switching power supply circuit of the present invention works in the continuous current mode, the currents of the primary winding S1 and the first secondary winding S21 of theflyback transformer 202 are not zero at the same time. When the utility model works in continuous current mode, the current waveforms of the primary winding S1 of itsflyback transformer 202 and the first secondary winding S21 are as shown in Figure 3, and Ip in Figure 3 is the primary of theflyback transformer 202 The current waveform of the winding S1, Is is the current waveform of the first secondary winding S21 of theflyback transformer 202, Ton is the conduction time of the first MOS transistor Q1, Toff is the cut-off time of the first MOS transistor Q1, Ts is the second A MOS transistor Q1 switching period.

断续电流模式为：本实用新型反激式开关电源电路处于空载或者轻载状态时，本实用新型反激式开关电源电路有可能工作于断续电流模式。此时，变压器初级控制电路208中的第一MOS管Q1的开关占空比较小，变压器初级控制电路208中的第一MOS管Q1关断后，反激式变压器202的第一次级绕组S21的电流线性减小，若在第一MOS管Q1导通之前，反激式变压器202的第一次级绕组S21的电流已经减小到0，则此时反激式变压器202的初级绕组S1和第一次级绕组S21的电流均为0，此时，本实用新型反激式开关电源电路工作于断续电流模式。当本实用新型工作于断续电流模式时，其反激式变压器202的初级绕组S1和第一次级绕组S21的电流波形如图4所示，图4中的Ip为反激式变压器202的初级绕组S1的电流波形，Is为反激式变压器202的第一次级绕组S21的电流波形，Ton为第一MOS管Q1的导通时间，Toff为第一MOS管Q1的截止时间，Ts为第一MOS管Q1开关周期。如图4所示，本实用新型工作于断续电流模式时，在一个开关周期未结束前，反激式变压器202的第一次级绕组S21的电流Ip已经减小到0，从而使得电流出现了断续的状态。The discontinuous current mode is: when the flyback switching power supply circuit of the present utility model is in the no-load or light-load state, the flyback switching power supply circuit of the present utility model may work in the discontinuous current mode. At this time, the switch duty ratio of the first MOS transistor Q1 in the transformerprimary control circuit 208 is small, and after the first MOS transistor Q1 in the transformerprimary control circuit 208 is turned off, the first secondary winding S21 of theflyback transformer 202 The current of theflyback transformer 202 decreases linearly. If the current of the first secondary winding S21 of theflyback transformer 202 has been reduced to 0 before the first MOS transistor Q1 is turned on, then the primary winding S1 of theflyback transformer 202 and the The current of the first secondary winding S21 is 0. At this time, the flyback switching power supply circuit of the present invention works in the discontinuous current mode. When the utility model works in the discontinuous current mode, the current waveforms of the primary winding S1 of itsflyback transformer 202 and the first secondary winding S21 are as shown in Figure 4, and Ip in Figure 4 is the current waveform of theflyback transformer 202 The current waveform of the primary winding S1, Is is the current waveform of the first secondary winding S21 of theflyback transformer 202, Ton is the conduction time of the first MOS transistor Q1, Toff is the cut-off time of the first MOS transistor Q1, and Ts is The switching cycle of the first MOS transistor Q1. As shown in Figure 4, when the utility model works in the discontinuous current mode, before the end of a switching cycle, the current Ip of the first secondary winding S21 of theflyback transformer 202 has been reduced to 0, so that the current appears intermittent state.

临界连续模式是连续电流模式与断续电流模式之间的一个过渡，临界连续模式为：变压器初级控制电路208中的第一MOS管Q1关断后，反激式变压器202的第一次级绕组S21的电流线性减小，在第一MOS管Q1开始导通时，反激式变压器202的第一次级绕组S21的电流刚好减小到0。当本实用新型工作于临界连续模式时，其反激式变压器202的初级绕组S1和第一次级绕组S21的电流波形如图5所示，图5中的Ip为反激式变压器202的初级绕组S1的电流波形，Is为反激式变压器202的第一次级绕组S21的电流波形，Ton为第一MOS管Q1的导通时间，Toff为第一MOS管Q1的截止时间，Ts为第一MOS管Q1开关周期。如图5所示，本实用新型工作于临界连续模式时，在一个开关周期结束时，反激式变压器202的第一次级绕组S21的电流Ip刚好减小到0，电流处于连续和断续的临界状态。The critical continuous mode is a transition between the continuous current mode and the discontinuous current mode. The critical continuous mode is: after the first MOS transistor Q1 in the transformerprimary control circuit 208 is turned off, the first secondary winding of theflyback transformer 202 The current of S21 decreases linearly. When the first MOS transistor Q1 starts to conduct, the current of the first secondary winding S21 of theflyback transformer 202 just decreases to zero. When the utility model works in the critical continuous mode, the current waveforms of the primary winding S1 of itsflyback transformer 202 and the first secondary winding S21 are as shown in Figure 5, and Ip in Figure 5 is the primary of theflyback transformer 202 The current waveform of the winding S1, Is is the current waveform of the first secondary winding S21 of theflyback transformer 202, Ton is the conduction time of the first MOS transistor Q1, Toff is the cut-off time of the first MOS transistor Q1, Ts is the second A MOS transistor Q1 switching cycle. As shown in Figure 5, when the utility model works in the critical continuous mode, at the end of a switching cycle, the current Ip of the first secondary winding S21 of theflyback transformer 202 just decreases to 0, and the current is between continuous and intermittent critical state.

本实施例中，反激式变压器202的初级绕组S1存储的能量为：（其中，Ip为初级绕组S1的电流；A_L为电感系数；Np为初级绕组S1的线圈匝数；f为反激式变压器202的工作频率）。In this embodiment, the energy stored in the primary winding S1 of theflyback transformer 202 is: (wherein, Ip is the current of the primary winding S1;_AL is the inductance; Np is the number of turns of the primary winding S1; f is the operating frequency of the flyback transformer 202).

反激式变压器202的第一次级绕组S21释放的能量为：

（其中，Is为第一次级绕组S21的电流；A_L为电感系数；Ns为第一次级绕组S21的线圈匝数；f为反激式变压器202的工作频率）。The energy released by the first secondary winding S21 of theflyback transformer 202 is:

(Wherein, Is is the current of the first secondary winding S21;_AL is the inductance; Ns is the number of coil turns of the first secondary winding S21; f is the operating frequency of the flyback transformer 202).

在忽略漏感的情况下，本实用新型的以上三种工作模式（连续电流模式、断续电流模式和临界连续模式）均满足：初级绕组S1储存的能量应该大于等于第一次级绕组S21释放的能量，即满足：In the case of ignoring the leakage inductance, the above three working modes (continuous current mode, discontinuous current mode and critical continuous mode) of the utility model are all satisfied: the energy stored in the primary winding S1 should be greater than or equal to the energy released by the first secondary winding S21 energy, which satisfies:

P_i≥P_S（理想状态时，取“=”号），即：P_i ≥ P_S (in an ideal state, take the "=" sign), that is:

$\frac{1}{2} I p^{2} {Np}^{2} f &GreaterEqual; \frac{1}{2} {Is}^{2} A_{L} {Ns}^{2} f$ ，即： $\frac{1}{2} I p^{2} {Np}^{2} f &Greater Equal; \frac{1}{2} {Is}^{2} A_{L} {NS}^{2} f$ ,Right now:

Is≤Ip●(Np/Ns)Is≤Ip (Np/Ns)

而当反激式变压器202的型号确定时，其初级绕组S1的线圈匝数及其第一次级绕组S21的线圈匝数就确实了，并且，由于Ip的最大值是由采样电阻RS的阻值决定的，因此，第一次级绕组S21的电流Is的最大值小于一个固定值，从而使得Is的最大值是可控的，即电子开关K1的峰值电流是可控的，从而可以选用适当功率值的MOS开关管作为本实用新型中主电压输出电路的电子开关K1，从而降低了电路的成本。When the type offlyback transformer 202 is determined, the number of turns of its primary winding S1 and the number of turns of its first secondary winding S21 are determined, and since the maximum value of Ip is determined by the resistance of the sampling resistor RS Therefore, the maximum value of the current Is of the first secondary winding S21 is less than a fixed value, so that the maximum value of Is is controllable, that is, the peak current of the electronic switch K1 is controllable, so that an appropriate The MOS switch tube of the power value is used as the electronic switch K1 of the main voltage output circuit in the utility model, thereby reducing the cost of the circuit.

本实用新型还提出一种反激式开关电源，该反激式开关电源包括反激式开关电源电路，其反激式开关电源电路的电路结构与上面实施例所述的反激式开关电源电路的电路结构相同，此处不再赘述。The utility model also proposes a flyback switching power supply, the flyback switching power supply includes a flyback switching power supply circuit, the circuit structure of the flyback switching power supply circuit is the same as that of the flyback switching power supply circuit described in the above embodiment The circuit structure is the same and will not be repeated here.

以上所述仅为本实用新型的优选实施例，并非因此限制本实用新型的专利范围，凡是利用本实用新型说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本实用新型的专利保护范围内。The above descriptions are only preferred embodiments of the present utility model, and are not therefore limiting the patent scope of the present utility model. Any equivalent structure or equivalent process transformation made by using the specification of the utility model and the contents of the accompanying drawings may be directly or indirectly used in Other relevant technical fields are all included in the patent protection scope of the present utility model in the same way.

Claims

1. inverse-excitation type switch power-supply circuit, comprise be used to the feeder ear that supply power voltage is provided, be used for described supply power voltage is carried out the flyback transformer of inverse-excitation type transformation, a principal voltage output circuit that is used for the output principal voltage, and main control circuit and a primary control circuit, described flyback transformer comprises armature winding and the first secondary winding, the described principal voltage output circuit of described master control circuit controls is exported described principal voltage, and according to the feedback current of the armature winding of described flyback transformer, control the ON time of described armature winding through described primary control circuit; It is characterized in that:

Described principal voltage output circuit comprises the first rectifier diode, the first filter capacitor and an electronic switch; The anode of described the first rectifier diode is connected with the Same Name of Ends of the first secondary winding of described flyback transformer, the different name end ground connection of described the first secondary winding, the negative electrode of described the first rectifier diode is connected with an end of described electronic switch, the other end of described electronic switch is connected with an end of described the first filter capacitor, this end of described the first filter capacitor is the voltage output end of described principal voltage output circuit, the other end ground connection of described the first filter capacitor, the control end of described electronic switch is connected with described main control circuit.

2. inverse-excitation type switch power-supply circuit according to claim 1, it is characterized in that, described the first filter capacitor is polar capacitor, and the positive pole of described the first filter capacitor is connected through the negative electrode of described electronic switch with described the first rectifier diode, the minus earth of described the first filter capacitor.

3. inverse-excitation type switch power-supply circuit according to claim 2 is characterized in that, described inverse-excitation type switch power-supply circuit comprises that also described flyback transformer also comprises the second subprime winding for the standby voltage output circuit of output standby voltage; The Same Name of Ends of described second subprime winding is connected with described standby voltage output circuit, the different name end ground connection of described second subprime winding.

4. inverse-excitation type switch power-supply circuit according to claim 3, it is characterized in that, described inverse-excitation type switch power-supply circuit also comprises an output capacitive loading, and an end of described output capacitive loading is connected with the positive pole of described the first filter capacitor, the other end ground connection of described output capacitive loading.

5. inverse-excitation type switch power-supply circuit according to claim 4, it is characterized in that, described feeder ear is connected with the different name end of the armature winding of described flyback transformer, and the Same Name of Ends of described armature winding is connected with described main control circuit through described primary control circuit.

6. inverse-excitation type switch power-supply circuit according to claim 5 is characterized in that, described standby voltage output circuit comprises the second rectifier diode and the second filter capacitor, and described the second filter capacitor is polar capacitor; The anode of described the second rectifier diode is connected with the Same Name of Ends of the second subprime winding of described flyback transformer, the negative electrode of described the second rectifier diode is connected with the positive pole of described the second filter capacitor, the voltage output end of the just very described standby voltage output circuit of described the second filter capacitor, the minus earth of described the second filter capacitor.

7. inverse-excitation type switch power-supply circuit according to claim 6 is characterized in that, described primary control circuit comprises the first metal-oxide-semiconductor and sampling resistor; Described the first metal-oxide-semiconductor is the PMOS pipe; The drain electrode of described the first metal-oxide-semiconductor is connected with the Same Name of Ends of the armature winding of described flyback transformer, its grid is connected with described main control circuit, its source electrode is connected with an end of described sampling resistor, and is connected with described main control circuit, the other end ground connection of described sampling resistor.

8. inverse-excitation type switch power-supply circuit according to claim 7, it is characterized in that, described electronic switch in the described principal voltage output circuit is the MOS switching tube, the source electrode of described MOS switching tube is connected with the negative electrode of described the first rectifier diode, its drain electrode is connected with the positive pole of described the first filter capacitor, and its grid is connected with described main control circuit.

9. an inverse-excitation type switch power-supply is characterized in that, comprises each described inverse-excitation type switch power-supply circuit among the claim 1-8.